1. Field of the Invention
This invention relates to semiconductor packages, and, more specifically, to solder balls and conductive wires for a semiconductor package, and an improved manufacturing method and evaporation method therefor.
2. Description of the Related Art
In general, solder balls for semiconductor packages are made of an alloy containing Sn, Pb, Ag and the like. Solder balls are widely used as input/output terminals for connecting the semiconductor package to external devices. Since the solder balls are readily fabricated and processed, their melting points are relatively low. In particular, solder balls are mainly in the form of input/output terminals arrayed on one side of the semiconductor package such as BGA, PBGA and so on.
Such solder balls can have various sizes and metal components according to the size, use and type of semiconductor packages and the taste of the customers. As recent regulations have been intensified against environmental pollution, lead-free solder balls made of only Sn also have become developed and commercialized.
The solder balls used in a semiconductor package are diverse in their types (size and metallic composition). In general, one fabrication process frequently uses several types of solder balls.
For example, because one ball bumping apparatus uses several kinds of semiconductor packages and several types of solder balls, management of the solder balls is more difficult. Management might be more or less easy if various types of solder balls could be managed by their respective ball bumping apparatuses. However, since the ball bumping apparatuses are restricted in number owing to their high price, only a few ball bumping apparatuses are used to perform solder bumping for various types of solder balls. This further increases the risk of mixing among different solder balls.
When the solder balls of different sizes and metallic compositions are mixed, the solder balls may not be tightly fixed via reflow process or may be fused with different diameters. This may cause various sequential problems in that the solder balls may not be electrically connected to external devices.
A conductive wire for a semiconductor package is generally a thin line which is made of Au, Al or Cu, and serves to connect a semiconductor die and a substrate (e.g., a lead frame, a printed circuit board, a circuit film, a circuit tape and so on). That is, the thin conductive wire is one of the structural materials of the semiconductor package, which electrically connects between the semiconductor die and the substrate for supporting the semiconductor die.
The diameter, metal, and composition of the conductive wire can be diversified according to the type and physical/mechanical characteristic of semiconductor packages or the taste of customers. In recent days, copper wires have been developed and commercialized that are more excellent in physical/electrical performance.
During the manufacturing process, a label is attached on a spool container in order to identify the conductive wire contained in the container. However, since the conductive wire is taken out of the container during wire bonding of the semiconductor package, it is difficult to thereafter identify the type or diameter of the conductive wire. As the conductive wires used in semiconductor packages are recently diversified in their types (diameter and metal), it is more difficult to discriminate a specific conductive wire from others if various types of conductive wires are used in the same fabrication process.
For example, one wire bonding apparatus uses several kinds of semiconductor packages and several types of conductive wires. Management of the conductive wires becomes more difficult because of the different types of wire that is used. Management might be more or less easy if various types of conductive wires could be managed by their respective wire bonding apparatuses. However, since the wire bonding apparatuses are restricted in number owing to their high price, only a few wire bonding apparatuses are used for wire bonding of various types of conductive wires. This further increases the risk of mixing among different conductive wires.
If the conductive wires of different diameters and metals are erroneously used, many problems are created in that the conductive wires are not tightly bonded to a semiconductor die or substrate, or in that mechanical, chemical or electrical characteristics may not be obtained at desired values.
Therefore a need existed to provide a semiconductor package and a method of producing a semiconductor package that overcomes the above problems.